Dutch police fired warning shots and used water cannon after rioting erupted in Rotterdam over new Covid-19 measures.
Protesters threw rocks and fireworks at them and set police cars ablaze.
Hundreds of protesters had gathered to show their anger at government plans for a Covid vaccine pass, and a ban on fireworks on New Year’s Eve.
The Netherlands imposed a three-week partial Covid lockdown last week as cases surged.
Police fired warning shots and direct shots “because the situation was life-threatening”, a police spokesperson told Reuters news agency.
At least two people have been injured as a result of the shots, they added.
Rotterdam has been placed under a state of emergency and its main station has been closed as a result of the violence.
Videos posted on social media showed burnt-out police cars and rioters hurling rocks at police in one of the city’s main shopping streets.
The Netherlands imposed fresh restrictions last Saturday after recording its highest numbers of Covid cases since the pandemic began.
The measures means restaurants and shops have to close earlier, and sports events must take place behind closed doors.
The protesters in Rotterdam voiced their disapproval at government proposals to introduce a “corona pass” for those vaccinated against coronavirus or who have recovered from the disease.
If introduced, only those showing the pass would be allowed into indoor venues, such as restaurants and bars.
Earlier on Friday, the government banned fireworks on 31 December for the second year in a row. The ban would prevent “extra strain on healthcare”, the government said.